1. Field of the Invention
With regard to the classification of art, this invention is believed to be found in the general class entitled "Material or Article Handling" and more particularly to those subclasses pertaining to column structures.
2. Description of Related Art
Columns for apparatus which are used for lifting of containers, drums and the like have been shown in U.S. Pat. No. 5,205,699 issued to me on Apr. 27, 1993; U.S. Pat. No. 4,954,037, issued to me on Sep. 4, 1990, and U.S. Pat. No. 4,797,050 issued to me on Jan. 10, 1989. Each of these lifting apparatus are designed for relatively short movement of the container.
The known prior art described above are limited to the distance of vertical travel of a container as well as the load bearing capacity of the column. It has been determined that there is a need for a lifting apparatus which has a small envelope column member. This desired column member must be capable of lifting a heavy load for an uninterrupted distance in the vicinity of 40 feet. It is also desired that the column have the ability to be used in a clean room environment.
The present invention improves the strength of a column member of a lifting apparatus while maintaining a small exterior envelope. The column of the present invention also allows a carriage member to be guided interior of the column member.